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Taxonomy and phylogeny of the section Chaetoceros(Chaetocerotaceae,Bacillariophyta),with description of two new species

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Journal of Oceanology and Limnology 2024年第4期42卷 1286-1311页

作者： Xudan LU mengyi zhai Nina LUNDHOLM Yang LI Guangdong Provincial Key Laboratory of Biotechnology for Plant Development Guangzhou Key Laboratory of Subtropical Biodiversity and BiomonitoringCollege of Life ScienceSouth China Normal UniversityGuangzhou 510631China Natural History Museum of Denmark University of CopenhagenCopenhagen K 1353Denmark

Chaetoceros Ehrenberg is one of the most diverse genera of planktonic *** species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely ***,the delimitations of some species are problematic because of limited morphological information in the classical *** strains of the section Chaetoceros were established,morphological features were studied using light and electron microscopy,and the hypervariable D 1-D 3 region of the nuclear ribosomal large subunit gene was sequenced to address phylogenetic *** species belonging to the section Chaetoceros were recorded,including two new species,*** *** *** *** hainanensis was characterized by straight chains,narrowly lanceolate to hexagonal apertures,sibling setae diverging in nearly right angles,stipule-shaped spines on terminal setae and arrowhead-shaped spines on intercalary *** had short straight chains,narrowly lanceolate apertures,arrowhead-shaped spines and circular poroids arranged in a grid pattern on terminal and intercalary *** phylogenetic analyses revealed six groups formed by 19 species within the section Chaetoceros,which was found to be *** subdivision of the section is still not well *** morphological characters within each group varied considerably and molecular information on more species are needed to enrich the phylogenetic profiling.

关键词： morphology large subunit ribosomal RNA encoding gene(LSU) section Chaetoceros Chaetoceros hainanensis Chaetoceros tridiscus

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Structure-Preserving Recurrent Neural Networks for a Class of Birkhoffian Systems

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Journal of Systems Science & Complexity 2024年第2期37卷 441-462页

作者： XIAO Shanshan CHEN mengyi ZHANG Ruili TANG Yifa LSEC ICMSECAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Mathematics and Statistics Beijing Jiaotong UniversityBeijing 100044China

In this paper,the authors propose a neural network architecture designed specifically for a class of Birkhoffian systems—The Newtonian *** proposed model utilizes recurrent neural networks(RNNs)and is based on a mathematical framework that ensures the preservation of the Birkhoffian *** authors demonstrate the effectiveness of the proposed model on a variety of problems for which preserving the Birkhoffian structure is important,including the linear damped oscillator,the Van der Pol equation,and a high-dimensional *** with the unstructured baseline models,the Newtonian neural network(NNN)is more data efficient,and exhibits superior generalization ability.

关键词： Birkhoffian system k(z,t)-symplectic neural networks recurrent neural network

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Multimodal Social Media Fake News Detection Based on Similarity Inference and Adversarial Networks

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Computers, Materials & Continua 2024年第4期79卷 581-605页

作者： Fangfang Shan Huifang Sun mengyi Wang College of Computer Zhongyuan University of TechnologyZhengzhou450007China Henan Key Laboratory of Cyberspace Situation Awareness Zhengzhou 450001China

As social networks become increasingly complex, contemporary fake news often includes textual descriptionsof events accompanied by corresponding images or videos. Fake news in multiple modalities is more likely tocreate a misleading perception among users. While early research primarily focused on text-based features forfake news detection mechanisms, there has been relatively limited exploration of learning shared representationsin multimodal (text and visual) contexts. To address these limitations, this paper introduces a multimodal modelfor detecting fake news, which relies on similarity reasoning and adversarial networks. The model employsBidirectional Encoder Representation from Transformers (BERT) and Text Convolutional Neural Network (Text-CNN) for extracting textual features while utilizing the pre-trained Visual Geometry Group 19-layer (VGG-19) toextract visual features. Subsequently, the model establishes similarity representations between the textual featuresextracted by Text-CNN and visual features through similarity learning and reasoning. Finally, these features arefused to enhance the accuracy of fake news detection, and adversarial networks have been employed to investigatethe relationship between fake news and events. This paper validates the proposed model using publicly availablemultimodal datasets from Weibo and Twitter. Experimental results demonstrate that our proposed approachachieves superior performance on Twitter, with an accuracy of 86%, surpassing traditional unimodalmodalmodelsand existing multimodal models. In contrast, the overall better performance of our model on the Weibo datasetsurpasses the benchmark models across multiple metrics. The application of similarity reasoning and adversarialnetworks in multimodal fake news detection significantly enhances detection effectiveness in this paper. However,current research is limited to the fusion of only text and image modalities. Future research directions should aimto further integrate f

关键词： Fake news detection attention mechanism image-text similarity multimodal feature fusion

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ALTERNATING OPTIMIZATION METHOD FOR ISOGEOMETRIC TOPOLOGY OPTIMIZATION WITH STRESS CONSTRAINTS

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Journal of Computational Mathematics 2024年第1期42卷 134-155页

作者： Xiaoya zhai School of Mathematical Sciences University of Science and Technology of ChinaHefei 230071China

Topology optimization (TO) has developed rapidly recently. However, topology optimization with stress constraints still faces many challenges due to its highly non-linear properties which will cause inefficient computation, iterative oscillation, and convergence guarantee problems. At the same time, isogeometric analysis (IGA) is accepted by more and more researchers, and it has become one important tool in the field of topology optimization because of its high fidelity. In this paper, we focus on topology optimization with stress constraints based on isogeometric analysis to improve computation efficiency and stability. A new hybrid solver combining the alternating direction method of multipliers and the method of moving asymptotes (ADMM-MMA) is proposed to solve this problem. We first generate an initial feasible point by alternating direction method of multipliers (ADMM) in virtue of the rapid initial descent property. After that, we adopt the method of moving asymptotes (MMA) to get the final results. Several benchmark examples are used to verify the proposed method, and the results show its feasibility and effectiveness.

关键词： Isogeometric topology optimization Stress constraints The ADMM-MMA solver

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Deep Learning Social Network Access Control Model Based on User Preferences

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 1029-1044页

作者： Fangfang Shan Fuyang Li Zhenyu Wang Peiyu Ji mengyi Wang Huifang Sun School of Computer Science Zhongyuan University of TechnologyZhengzhou450007China Henan Key Laboratory of Cyberspace Situation Awareness Zhengzhou450001China

A deep learning access controlmodel based on user preferences is proposed to address the issue of personal privacy leakage in social ***,socialusers andsocialdata entities are extractedfromthe social networkandused to construct homogeneous and heterogeneous ***,a graph neural networkmodel is designed based on user daily social behavior and daily social data to simulate the dissemination and changes of user social preferences and user personal preferences in the social ***,high-order neighbor nodes,hidden neighbor nodes,displayed neighbor nodes,and social data nodes are used to update user nodes to expand the depth and breadth of user ***,a multi-layer attention network is used to classify user nodes in the homogeneous graph into two classes:allow access and deny *** fine-grained access control problem in social networks is transformed into a node classification problem in a graph neural *** model is validated using a dataset and compared with other methods without losing *** model improved accuracy by 2.18%compared to the baseline method GraphSAGE,and improved F1 score by 1.45%compared to the baseline method,verifying the effectiveness of the model.

关键词： Graph neural networks user preferences access control social network

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DCVAE-adv:A Universal Adversarial Example Generation Method for White and Black Box Attacks

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Tsinghua Science and Technology 2024年第2期29卷 430-446页

作者： Lei Xu Junhai zhai College of Mathematics and Information Science Hebei UniversityBaoding 071002China

Deep neural network(DNN)has strong representation learning ability,but it is vulnerable and easy to be fooled by adversarial *** order to handle the vulnerability of DNN,many methods have been *** general idea of existing methods is to reduce the chance of DNN models being fooled by observing some designed adversarial examples,which are generated by adding perturbations to the original *** this paper,we propose a novel adversarial example generation method,called *** from the existing methods,DCVAE-adv constructs adversarial examples by mixing both explicit and implicit perturbations without using original ***,the proposed method can be applied to both white box and black box *** addition,in the inference stage,the adversarial examples can be generated without loading the original images into memory,which greatly reduces the memory *** compared DCVAE-adv with three most advanced adversarial attack algorithms:FGSM,AdvGAN,and AdvGAN++.The experimental results demonstrate that DCVAE-adv is superior to these state-of-the-art methods in terms of attack success rate and transfer ability for targeted *** code is available at https://***/xzforeverlove/DCVAE-adv.

关键词： deep neural network adversarial examples white box attack black box attack robustness

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Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 712-724页

作者： Dajun zhai Xiaoping Li Jun Shen College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg *** kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/*** characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic *** was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and *** nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in *** effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge *** MAO coating on Zr-FSP sample had good wettability and corrosion ***,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

关键词： AZ91D Mg alloy microarc oxidation friction stir processing ZrO_(2) TiO_(2) β-Mg_(17)Al_(12)

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Dynamics modeling and electromechanical coupling characteristics analysis of cage induction motors

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Science China(Technological Sciences) 2024年第3期67卷 709-724页

作者： ZHOU ZiWei CHEN ZaiGang zhai WanMing State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Induction motors, as typical electromechanical energy conversion devices, have received limited attention in previous studies on electromechanical coupling vibrations, precise modeling, and the use of electromechanical coupling effects for fault diagnosis and condition assessment in motor drive systems. This study proposes a comprehensive model of cage induction motors that integrates the multiple coupled circuit model with a rotor-bearing dynamics model. The model accounts for the linear increase in the magnetomotive force across the slot and incorporates the skidding characteristics of bearings in the rotor-bearing system. By calculating the time-varying mutual inductance parameters based on the air-gap distribution in the vibration environment, the electromechanical coupling vibration of the cage motor is investigated. Furthermore, this study examines the electromechanical coupling vibration characteristics influenced by various factors, including bearing clearances, radial loads, and the vertical excitation frequencies of the stators. The results show that the proposed model improves the excitation inputs for the electrical and mechanical systems of the motor compared with conventional models. Increased bearing clearance and radial load affect the current and torque similarly but have opposite effects on the slip ratio. This study provides a deeper understanding of electromechanical coupling mechanisms and facilitates the use of such phenomena for fault diagnosis and condition assessment in motor-driven systems.

关键词： cage induction motors rotor-bearing dynamics mutual inductance electromechanical testing current signal analysis

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Bivariate attribution of the compound hot and dry summer of 2022 on the Tibetan Plateau

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Science China Earth Sciences 2024年第7期67卷 2122-2136页

作者： Baiquan ZHOU Panmao zhai Zhen LIAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China

The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic *** absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least *** the susceptibility of the TP to climate change,this study employed large-ensemble simulations from the HadGEM3-A-N216 attribution system,together with a copula-based joint probability distribution,to investigate the influence of anthropogenic forcing,primarily global greenhouse gas emissions,on this unprecedented compound hot and dry event(CHDE).Findings revealed that the return period for the 2022 CHDE on the TP exceeds 4000 years,as determined from the fitted joint distributions derived using observational data spanning *** CHDE was directly linked to large-scale circulation anomalies,including the control of equivalent-barotropic high-pressure anomalies and the northward displacement of the subtropical westerly jet ***,anthropogenic forcing has,to some extent,promoted the surface warming and increased variability in precipitation on the TP in summer,establishing conditions conducive for the 2022 CHDE from a long-term climate change *** return period for a 2022-like CHDE on the TP was estimated to be approximately 283 years(142-613 years)by the large ensemble forced by both anthropogenic activities and natural ***,ensemble simulations driven solely by natural forcing indicated that the likelihood of occurrence of a 2022-like CHDE was almost *** outcomes underscore that the contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%,implying that without anthropogenically induced global warming,a comparable CHDE akin to that observed in 2022 on the TP would not be possible.

关键词： Compound hot and dry event Tibetan Plateau Bivariate event attribution Anthropogenic forcing

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Heparin-induced thrombocytopenia thrombosis after pancreaticoduodenectomy without definitive prophylactic or therapeutic use of heparin: a case report

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胰腺病学杂志(英文) 2024年第2期7卷 164-166页

作者： Wang mengyi Huang Nan Liu Qiaofei Liao Quan Department of General Surgery Key Laboratory of Research in Pancreatic Tumor State Key Laboratory of Complex Severe and Rare Diseases Peking Union Medical College Hospital Chinese Academy of Medical Science and Peking Union Medical College# Shuaifuyuan Dongcheng District Beijing China

Heparin-induced thrombocytopenia thrombosis (HITT) is a rare and potentially life-threatening complication after abdominal surgery, and it always occurs after the prophylactic or therapeutic use of heparin. HITT after pancreaticoduodenectomy (PD) has not been reported before. Herein, we reported a case of HITT after PD without prophylactic or therapeutic use of heparin. A 74-year-old female patient who suffered resectable pancreatic head cancer was transferred to our center for surgery. An open PD procedure was performed, and the operation was smooth. No heparin was used after surgery. Nine days after surgery, the platelet sharply declined to 48 × 109/L (100-350), and the D-dimer soared up to 33.56 mg/L (0-0.55). Ultrasound examination showed vein thrombosis in both the lower limb and the right upper limb. HIT-antibody was 6.3 U/mL (0-0.6). The diagnosis of HITT was confirmed. Fondaparinux was used. On postoperative day (POD) 23, the platelet recovered to the normal range. On POD 27, she was discharged without thromboembolism or active bleeding, and oral rivaroxaban was prescribed. One month after discharge, the platelet remained normal, and she did not complain of discomfort.

关键词： Heparin-induced thrombocytopenia Pancreatic cancer Pancreaticoduodenectomy Perioperative anticoagulation

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